Increase the Visibility of Microbial Growth in a Winogradsky Column by Substituting Diatomaceous Earth for Sediment

• Main Author: Thomas G. Benoit
• Format: Article
• Language: English
• Published: American Society for Microbiology 2015-02-01
• Series: Journal of Microbiology & Biology Education
• Subjects: Winogradsky column; diatomaceous earth; sulfur cycle; sediment bacteria; visible microbial growth
• Online Access: http://jmbesubmissions.asm.org/index.php/jmbe/article/view/889

The difficulty students have seeing the color associated with microbial growth in a traditional Winogradsky column can be overcome by substituting diatomaceous earth (DE) for sediment. Microbial growth in a DE column is visible from the early stages of ecological succession and the colors produced appear more vibrant. A flat-sided tissue culture flask can be used as a column container to provide a large surface area for observation. The enhanced visual experience provided by a DE column increases student engagement and learning.   Editor's Note: The ASM advocates that students must successfully demonstrate the ability to explain and practice safe laboratory techniques. For more information, read the laboratory safety section of the ASM Curriculum Recommendations: Introductory Course in Microbiology and the Guidelines for Biosafety in Teaching Laboratories, available at www.asm.org. The Editors of JMBE recommend that adopters of the protocols included in this article follow a minimum of Biosafety Level 1 practices.